Data transmission method and device in wireless communication system

ABSTRACT

A method and a user equipment (UE) are provided for transmitting uplink data in a wireless communication system. Uplink data is mapped to resource elements corresponding to a physical uplink shared channel (PUSCH) in a UE-specific aperiodic sounding reference signal (SRS) subframe. The UE-specific aperiodic SRS subframe includes a single carrier frequency division multiple access (SC-FDMA) symbol reserved for an aperiodic SRS. The aperiodic SRS is transmitted in the reserved SC-FDMA symbol when triggered by a base station. The uplink data is not mapped to the SC-FDMA symbol reserved for the aperiodic SRS regardless of whether the aperiodic SRS is transmitted in the reserved SC-FDMA symbol or not. The mapped uplink data is transmitted to the base station via the UE-specific aperiodic SRS subframe.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of co-pending U.S. application Ser.No. 13/578,486, filed on Aug. 10, 2012, which is the National Phase ofPCT/KR2011/000971 filed on Feb. 14, 2011, which claims priority under 35U.S.C. 119(e) to U.S. Provisional Application Nos. 61/303,674 filed onFeb. 12, 2010, 61/394,360 filed on Oct. 19, 2010, 61/405,184 filed onOct. 20, 2010, 61/409,096 filed Nov. 1, 2010, 61/409,531 filed Nov. 2,2010, 61/415,338 filed Nov. 18, 2010, 61/415,354 filed on Nov. 19, 2010,61/415,747 filed on Nov. 19, 2010 and 61/427,484 filed on Dec. 28, 2010and under 35 U.S.C. 119(a) to Patent Application No. 10-2011-0012298filed in Republic of Korea on Feb. 11, 2011, all of which are herebyexpressly incorporated by reference into the present application.

BACKGROUND OF THE INVENTION

The present invention relates to wireless communication and, morespecifically, to a data transmission method and apparatus in a wirelesscommunication system.

In wireless communication systems, it is necessary to estimate an uplinkchannel or a downlink channel for the purpose of the transmission andreception of data, the acquisition of system synchronization, and thefeedback of channel information. In wireless communication systemenvironments, fading is generated because of multi-path time latency. Aprocess of restoring a transmit signal by compensating for thedistortion of the signal resulting from a sudden change in theenvironment due to such fading is referred to as channel estimation. Itis also necessary to measure the state of a channel for a cell to whicha user equipment belongs or other cells. To estimate a channel ormeasure the state of a channel, a reference signal (RS) which is knownto both a transmitter and a receiver can be used.

A subcarrier used to transmit the reference signal is referred to as areference signal subcarrier, and a subcarrier used to transmit data isreferred to as a data subcarrier. In an OFDM system, a method ofassigning the reference signal includes a method of assigning thereference signal to all the subcarriers and a method of assigning thereference signal between data subcarriers. The method of assigning thereference signal to all the subcarriers is performed using a signalincluding only the reference signal, such as a preamble signal, in orderto obtain the throughput of channel estimation. If this method is used,the performance of channel estimation can be improved as compared withthe method of assigning the reference signal between data subcarriersbecause the density of reference signals is in general high. However,since the amount of transmitted data is small in the method of assigningthe reference signal to all the subcarriers, the method of assigning thereference signal between data subcarriers is used in order to increasethe amount of transmitted data. If the method of assigning the referencesignal between data subcarriers is used, the performance of channelestimation can be deteriorated because the density of reference signalsis low. Accordingly, the reference signals should be properly arrangedin order to minimize such deterioration.

A receiver can estimate a channel by separating information about areference signal from a received signal because it knows the informationabout a reference signal and can accurately estimate data, transmittedby a transmit stage, by compensating for an estimated channel value.Assuming that the reference signal transmitted by the transmitter is p,channel information experienced by the reference signal duringtransmission is h, thermal noise occurring in the receiver is n, and thesignal received by the receiver is y, it can result in y=h·p+n. Here,since the receiver already knows the reference signal p, it can estimatea channel information value ĥ using Equation 1 in the case in which aLeast Square (LS) method is used.

ĥ=y/p=h+n/p=h+{circumflex over (n)}  [Equation 1]

The accuracy of the channel estimation value ĥ estimated using thereference signal p is determined by the value {circumflex over (n)}. Toaccurately estimate the value h, the value {circumflex over (n)} mustconverge on 0. To this end, the influence of the value {circumflex over(n)} has to be minimized by estimating a channel using a large number ofreference signals. A variety of algorithms for a better channelestimation performance may exist.

An uplink RS may be divided into a demodulation reference signal (DMRS)and a sounding reference signal (SRS). The DMRS is an RS used in channelestimation for demodulating a received signal. The DMRS may be combinedwith the transmission of a PUSCH or a PUCCH. The SRS is an RStransmitted from UE to a BS for uplink scheduling. The BS estimates anuplink channel through a received SRS and uses the estimated uplinkchannel in uplink scheduling.

Meanwhile, an SRS may be periodically transmitted or may be trigged by aBS when the BS needs to transmit an SRS and aperiodically transmitted. Asubframe configured to transmit an SRS may be previously determined, anduplink data may be transmitted in a relevant subframe through a physicaluplink shared channel (PUSCH).

If the transmission of an SRS and the transmission of uplink datathrough a PUSCH are configured so that they are performed in onesubframe, there is a need for a method of performing the transmissionefficiently.

SUMMARY OF THE INVENTION

The present invention provides a data transmission method and apparatusin a wireless communication system.

In an aspect, a data transmission method by a user equipment (UE) in awireless communication system is provided. The data transmission methodincludes transmitting a sounding reference signal (SRS) and uplink dataon a physical uplink shared channel (PUSCH) in an SRS subframe, whereina single carrier-frequency division multiple access (SC-FDMA) symbolallocated to the SRS and an SC-FDMA symbol allocated to the PUSCH do notoverlap with each other within the SRS subframe.

The SRS subframe may be one of a plurality of UE-specific SRS subframesconfigured by a UE-specific aperiodic SRS parameter.

The UE-specific aperiodic SRS parameter may indicate a periodicity andan offset of the plurality of UE-specific SRS subframes.

The UE-specific aperiodic SRS parameter may be given by a higher layer.

The plurality of UE-specific SRS subframes may be a subset of aplurality of cell-specific SRS subframes configured by a cell-specificSRS parameter.

The SRS subframe may be one of a plurality of cell-specific SRSsubframes configured by a cell-specific SRS parameter.

The PUSCH may be subject to rate matching except the SC-FDMA symbolallocated to the SRS.

The SC-FDMA symbol allocated to the SRS may be a last SC-FDMA symbol ofthe SRS subframe.

A bandwidth of some of or all SC-FDMA symbols allocated to the SRS maybe allocated for a transmission of the SRS.

In another aspect, a resource mapping method in a wireless communicationsystem is provided. The resource mapping method includes mappingphysical resource blocks assigned for physical uplink shared channel(PUSCH) transmission, to corresponding resource elements (REs) within asubframe, wherein the REs are not included in a single carrier-frequencydivision multiple access (SC-FDMA) symbol reserved for aperiodicsounding reference signal (SRS) transmission.

The subframe may be one of a plurality of UE-specific SRS subframesconfigured by a UE-specific aperiodic SRS parameter.

The UE-specific aperiodic SRS parameter may indicate a periodicity andan offset of the plurality of UE-specific SRS subframes.

The UE-specific aperiodic SRS parameter may be given by a higher layer.

The plurality of UE-specific SRS subframes may be a subset of aplurality of cell-specific SRS subframes configured by a cell-specificSRS parameter.

The SRS subframe may be one of a plurality of cell-specific SRSsubframes configured by a cell-specific SRS parameter.

The PUSCH may be subject to rate matching except the SC-FDMA symbolallocated to the aperiodic SRS.

The SC-FDMA symbol allocated to the aperiodic SRS may be a last SC-FDMAsymbol of the SRS subframe.

The resource mapping method may further include transmitting theaperiodic SRS through the SC-FDMA symbol allocated to the aperiodic SRS.

In another aspect, a user equipment in a wireless communication systemis provided. The user equipment includes a radio frequency (RF) unittransmitting a sounding reference signal (SRS) and uplink data on aphysical uplink shared channel (PUSCH) in an SRS subframe, and aprocessor connected to the RF unit, wherein a single carrier-frequencydivision multiple access (SC-FDMA) symbol allocated to the SRS and anSC-FDMA symbol allocated to the PUSCH do not overlap with each otherwithin the SRS subframe.

If an aperiodic SRS triggered by a BS and a physical uplink sharedchannel (PUSCH) are configured so that they are transmitted in onesubframe, uplink resources can be efficiently allocated and reliabilityof SRS transmission can also be maintained.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a wireless communication system.

FIG. 2 shows the structure of a radio frame in 3GPP LTE.

FIG. 3 shows an example of a resource grid of a single downlink slot.

FIG. 4 shows the structure of a downlink subframe.

FIG. 5 shows the structure of an uplink subframe.

FIG. 6, including (a) and (b), shows an example of a transmitter and areceiver which constitute a carrier aggregation system.

FIG. 7, including (a) and (b), and FIG. 8, including (a) and (b), areother examples of a transmitter and a receiver which constitute acarrier aggregation system.

FIG. 9, including (a) and (b), shows an example of an asymmetric carrieraggregation system.

FIG. 10 is an example of a process of processing an uplink sharedchannel (UL-SCH) transport channel.

FIG. 11 is an example of a configuration regarding the proposed methodof transmitting data in an SRS subframe.

FIG. 12 is an embodiment of the proposed data transmission method.

FIG. 13 is an embodiment of the proposed resource mapping method.

FIG. 14 is another example of a configuration regarding the proposedmethod of transmitting data in an SRS subframe.

FIG. 15 is a block diagram of a BS and UE in which the embodiments ofthe present invention are embodied.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

The following technique may be used for various wireless communicationsystems such as code division multiple access (CDMA), a frequencydivision multiple access (FDMA), time division multiple access (TDMA),orthogonal frequency division multiple access (OFDMA), singlecarrier-frequency division multiple access (SC-FDMA), and the like. TheCDMA may be implemented as a radio technology such as universalterrestrial radio access (UTRA) or CDMA2000. The TDMA may be implementedas a radio technology such as a global system for mobile communications(GSM)/general packet radio service (GPRS)/enhanced data rates for GSMevolution (EDGE). The OFDMA may be implemented by a radio technologysuch as institute of electrical and electronics engineers (IEEE) 802.11(Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, E-UTRA (evolved UTRA), andthe like. IEEE 802.16m, an evolution of IEEE 802.16e, provides backwardcompatibility with a system based on IEEE 802.16e. The UTRA is part of auniversal mobile telecommunications system (UMTS). 3GPP (3rd generationpartnership project) LTE (long term evolution) is part of an evolvedUMTS (E-UMTS) using the E-UTRA, which employs the OFDMA in downlink andthe SC-FDMA in uplink. LTE-A (advanced) is an evolution of 3GPP LTE.

Hereinafter, for clarification, LTE-A will be largely described, but thetechnical concept of the present invention is not meant to be limitedthereto.

FIG. 1 shows a wireless communication system.

The wireless communication system 10 includes at least one base station(BS) 11. Respective BSs 11 provide a communication service to particulargeographical areas 15 a, 15 b, and 15 c (which are generally calledcells). Each cell may be divided into a plurality of areas (which arecalled sectors). A user equipment (UE) 12 may be fixed or mobile and maybe referred to by other names such as MS (mobile station), MT (mobileterminal), UT (user terminal), SS (subscriber station), wireless device,PDA (personal digital assistant), wireless modem, handheld device. TheBS 11 generally refers to a fixed station that communicates with the UE12 and may be called by other names such as eNB (evolved-NodeB), BTS(base transceiver system), access point (AP), etc.

In general, a UE belongs to one cell, and the cell to which a UE belongsis called a serving cell. A BS providing a communication service to theserving cell is called a serving BS. The wireless communication systemis a cellular system, so a different cell adjacent to the serving cellexists. The different cell adjacent to the serving cell is called aneighbor cell. A BS providing a communication service to the neighborcell is called a neighbor BS. The serving cell and the neighbor cell arerelatively determined based on a UE.

This technique can be used for downlink or uplink. In general, downlinkrefers to communication from the BS 11 to the UE 12, and uplink refersto communication from the UE 12 to the BS 11. In downlink, a transmittermay be part of the BS 11 and a receiver may be part of the UE 12. Inuplink, a transmitter may be part of the UE 12 and a receiver may bepart of the BS 11.

The wireless communication system may be any one of a multiple-inputmultiple-output (MIMO) system, a multiple-input single-output (MISO)system, a single-input single-output (SISO) system, and a single-inputmultiple-output (SIMO) system. The MIMO system uses a plurality oftransmission antennas and a plurality of reception antennas. The MISOsystem uses a plurality of transmission antennas and a single receptionantenna. The SISO system uses a single transmission antenna and a singlereception antenna. The SIMO system uses a single transmission antennaand a plurality of reception antennas. Hereinafter, a transmissionantenna refers to a physical or logical antenna used for transmitting asignal or a stream, and a reception antenna refers to a physical orlogical antenna used for receiving a signal or a stream.

FIG. 2 shows the structure of a radio frame in 3GPP LTE.

It may be referred to Paragraph 5 of “Technical Specification GroupRadio Access Network; Evolved Universal Terrestrial Radio Access(E-UTRA); Physical channels and modulation (Release 8)” to 3GPP (3rdgeneration partnership project) TS 36.211 V8.2.0 (2008-03). Referring toFIG. 2, the radio frame includes 10 subframes, and one subframe includestwo slots. The slots in the radio frame are numbered by #0 to #19. Atime taken for transmitting one subframe is called a transmission timeinterval (TTI). The TTI may be a scheduling unit for a datatransmission. For example, a radio frame may have a length of 10 ms, asubframe may have a length of 1 ms, and a slot may have a length of 0.5ms.

One slot includes a plurality of orthogonal frequency divisionmultiplexing (OFDM) symbols in a time domain and a plurality ofsubcarriers in a frequency domain. Since 3GPP LTE uses OFDMA indownlink, the OFDM symbols are used to express a symbol period. The OFDMsymbols may be called by other names depending on a multiple-accessscheme. For example, when a single carrier frequency division multipleaccess (SC-FDMA) is in use as an uplink multi-access scheme, the OFDMsymbols may be called SC-FDMA symbols. A resource block (RB), a resourceallocation unit, includes a plurality of continuous subcarriers in aslot. The structure of the radio frame is merely an example. Namely, thenumber of subframes included in a radio frame, the number of slotsincluded in a subframe, or the number of OFDM symbols included in a slotmay vary.

3GPP LTE defines that one slot includes seven OFDM symbols in a normalcyclic prefix (CP) and one slot includes six OFDM symbols in an extendedCP.

The wireless communication system may be divided into a frequencydivision duplex (FDD) scheme and a time division duplex (TDD) scheme.According to the FDD scheme, an uplink transmission and a downlinktransmission are made at different frequency bands. According to the TDDscheme, an uplink transmission and a downlink transmission are madeduring different periods of time at the same frequency band. A channelresponse of the TDD scheme is substantially reciprocal. This means thata downlink channel response and an uplink channel response are almostthe same in a given frequency band. Thus, the TDD-based wirelesscommunication system is advantageous in that the downlink channelresponse can be obtained from the uplink channel response. In the TDDscheme, the entire frequency band is time-divided for uplink anddownlink transmissions, so a downlink transmission by the BS and anuplink transmission by the UE can be simultaneously performed. In a TDDsystem in which an uplink transmission and a downlink transmission arediscriminated in units of subframes, the uplink transmission and thedownlink transmission are performed in different subframes.

FIG. 3 shows an example of a resource grid of a single downlink slot.

A downlink slot includes a plurality of OFDM symbols in the time domainand N_(RB) number of resource blocks (RBs) in the frequency domain. TheN_(RB) number of resource blocks included in the downlink slot isdependent upon a downlink transmission bandwidth set in a cell. Forexample, in an LTE system, N_(RB) may be any one of 60 to 110. Oneresource block includes a plurality of subcarriers in the frequencydomain. An uplink slot may have the same structure as that of thedownlink slot.

Each element on the resource grid is called a resource element. Theresource elements on the resource grid can be discriminated by a pair ofindexes (k,l) in the slot. Here, k (k=0, . . . , N_(RB)×12−1) is asubcarrier index in the frequency domain, and 1 is an OFDM symbol indexin the time domain.

Here, it is illustrated that one resource block includes 7×12 resourceelements made up of seven OFDM symbols in the time domain and twelvesubcarriers in the frequency domain, but the number of OFDM symbols andthe number of subcarriers in the resource block are not limited thereto.The number of OFDM symbols and the number of subcarriers may varydepending on the length of a cyclic prefix (CP), frequency spacing, andthe like. For example, in case of a normal CP, the number of OFDMsymbols is 7, and in case of an extended CP, the number of OFDM symbolsis 6. One of 128, 256, 512, 1024, 1536, and 2048 may be selectively usedas the number of subcarriers in one OFDM symbol.

FIG. 4 shows the structure of a downlink subframe.

A downlink subframe includes two slots in the time domain, and each ofthe slots includes seven OFDM symbols in the normal CP. First three OFDMsymbols (maximum four OFDM symbols with respect to a 1.4 MHz bandwidth)of a first slot in the subframe corresponds to a control region to whichcontrol channels are allocated, and the other remaining OFDM symbolscorrespond to a data region to which a physical downlink shared channel(PDSCH) is allocated.

The PDCCH may carry a transmission format and a resource allocation of adownlink shared channel (DL-SCH), resource allocation information of anuplink shared channel (UL-SCH), paging information on a PCH, systeminformation on a DL-SCH, a resource allocation of an higher layercontrol message such as a random access response transmitted via aPDSCH, a set of transmission power control commands with respect toindividual UEs in a certain UE group, an activation of a voice overinternet protocol (VoIP), and the like. A plurality of PDCCHs may betransmitted in the control region, and a UE can monitor a plurality ofPDCCHs. The PDCCHs are transmitted on one or an aggregation of aplurality of consecutive control channel elements (CCE). The CCE is alogical allocation unit used to provide a coding rate according to thestate of a wireless channel. The CCE corresponds to a plurality ofresource element groups. The format of the PDCCH and an available numberof bits of the PDCCH are determined according to an associative relationbetween the number of the CCEs and a coding rate provided by the CCEs.

The BS determines a PDCCH format according to a DCI to be transmitted tothe UE, and attaches a cyclic redundancy check (CRC) to the DCI. Aunique radio network temporary identifier (RNTI) is masked on the CRCaccording to the owner or the purpose of the PDCCH. In case of a PDCCHfor a particular UE, a unique identifier, e.g., a cell-RNTI (C-RNTI), ofthe UE, may be masked on the CRC. Or, in case of a PDCCH for a pagingmessage, a paging indication identifier, e.g., a paging-RNTI (P-RNTI),may be masked on the CRC. In case of a PDCCH for a system informationblock (SIB), a system information identifier, e.g., a systeminformation-RNTI (SI-RNTI), may be masked on the CRC. In order toindicate a random access response, i.e., a response to a transmission ofa random access preamble of the UE, a random access-RNTI (RA-RNTI) maybe masked on the CRC.

FIG. 5 shows the structure of an uplink subframe.

An uplink subframe may be divided into a control region and a dataregion in the frequency domain. A physical uplink control channel(PUCCH) for transmitting uplink control information is allocated to thecontrol region. A physical uplink shared channel (PUCCH) fortransmitting data is allocated to the data region. If indicated by ahigher layer, the user equipment may support simultaneous transmissionof the PUCCH and the PUSCH.

The PUCCH for one UE is allocated in an RB pair. RBs belonging to the RBpair occupy different subcarriers in each of a 1^(st) slot and a 2^(nd)slot. A frequency occupied by the RBs belonging to the RB pair allocatedto the PUCCH changes at a slot boundary. This is called that the RB pairallocated to the PUCCH is frequency-hopped at a slot boundary. Since theUE transmits UL control information over time through differentsubcarriers, a frequency diversity gain can be obtained. In the figure,m is a location index indicating a logical frequency-domain location ofthe RB pair allocated to the PUCCH in the subframe.

Uplink control information transmitted on the PUCCH may include a HARQACK/NACK, a channel quality indicator (CQI) indicating the state of adownlink channel, a scheduling request (SR) which is an uplink radioresource allocation request, and the like.

The PUSCH is mapped to a uplink shared channel (UL-SCH), a transportchannel. Uplink data transmitted on the PUSCH may be a transport block,a data block for the UL-SCH transmitted during the TTI. The transportblock may be user information. Or, the uplink data may be multiplexeddata. The multiplexed data may be data obtained by multiplexing thetransport block for the UL-SCH and control information. For example,control information multiplexed to data may include a CQI, a precodingmatrix indicator (PMI), an HARQ, a rank indicator (RI), or the like. Orthe uplink data may include only control information.

3GPP LTE-A supports a carrier aggregation system. 3GPP TR 36.815 V9.0.0(2010-3) may be incorporated herein by reference to describe the carrieraggregation system.

The carrier aggregation system implies a system that configures awideband by aggregating one or more carriers having a bandwidth smallerthan that of a target wideband when the wireless communication systemintends to support the wideband. The carrier aggregation system can alsobe referred to as other tennis such as a bandwidth aggregation system orthe like. The carrier aggregation system can be divided into acontiguous carrier aggregation system in which carriers are contiguousto each other and a non-contiguous carrier aggregation system in whichcarriers are separated from each other. In the contiguous carrieraggregation system, a guard band may exist between CCs. A CC which is atarget when aggregating one or more CCs can directly use a bandwidththat is used in the legacy system in order to provide backwardcompatibility with the legacy system. For example, a 3GPP LTE system cansupport a bandwidth of 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz, and 20MHz, and a 3GPP LTE-A system can configure a wideband of 20 MHz orhigher by using only the bandwidth of the 3GPP LTE system.Alternatively, the wideband can be configured by defining a newbandwidth without having to directly use the bandwidth of the legacysystem.

In the carrier aggregation system, a UE can transmit or receive one or aplurality of carriers simultaneously according to capacity. An LTE-A UEcan transmit or receive a plurality of carriers simultaneously. An LTErel-8 UE can transmit or receive only one carrier when each of carriersconstituting the carrier aggregation system is compatible with an LTErel-8 system. Therefore, when the number of carriers used in uplink isequal to the number of carriers used in downlink, it is necessary toconfigure such that all CCs are compatible with LTE rel-8.

In order to efficiently use the plurality of carriers, the plurality ofcarriers can be managed in a media access control (MAC). Totransmit/receive the plurality of carriers, a transmitter and a receiverboth have to be able to transmit/receive the plurality of carriers.

FIG. 6, including (a) and (b), shows an example of a transmitter and areceiver which constitute a carrier aggregation system.

In the transmitter of FIG. 6(a), one MAC transmits and receives data bymanaging and operating all of n carriers. This is also applied to thereceiver of FIG. 6(b). From the perspective of the receiver, onetransport block and one HARQ entity may exist per CC. A UE can bescheduled simultaneously for a plurality of CCs. The carrier aggregationsystem of FIG. 6 can apply both to a contiguous carrier aggregationsystem and a non-contiguous carrier aggregation system. The respectivecarriers managed by one MAC do not have to be contiguous to each other,which results in flexibility in terms of resource management.

FIG. 7, including (a) and (b), and FIG. 8, including (a) and (b), areother examples of a transmitter and a receiver which constitute acarrier aggregation system.

In the transmitter of FIG. 7(a) and the receiver of FIG. 7(b), one MACmanages only one carrier. That is, the MAC and the carrier are 1:1mapped. In the transmitter of FIG. 8(a) and the receiver of FIG. 8(b), aMAC and a carrier are 1:1 mapped for some carriers, and regarding theremaining carriers, one MAC controls a plurality of CCs. That is,various combinations are possible based on a mapping relation betweenthe MAC and the carrier.

The carrier aggregation system of FIG. 6 to FIG. 8 includes n carriers.The respective carriers may be contiguous to each other or may beseparated from each other. The carrier aggregation system can apply bothto uplink and downlink transmissions. In a TDD system, each carrier isconfigured to be able to perform uplink transmission and downlinktransmission. In an FDD system, a plurality of CCs can be used bydividing them for an uplink usage and a downlink usage. In a typical TDDsystem, the number of CCs used in uplink transmission is equal to thatused in downlink transmission, and each carrier has the same bandwidth.The FDD system can configure an asymmetric carrier aggregation system byallowing the number of carriers and the bandwidth to be differentbetween uplink and downlink transmissions.

FIG. 9, including (a) and (b), shows an example of an asymmetric carrieraggregation system.

FIG. 9(a) is an example of a carrier aggregation system in which thenumber of downlink component carriers (CCs) is larger than the number ofUL CCs. Downlink CCs #1 and #2 correspond to an UL CC #1, and DL CCs #2and #4 correspond to an UL CC #2. FIG. 9(b) is an example of a carrieraggregation system in which the number of DL CCs is larger than thenumber of UL CCs. A DL CC #1 correspond to UL CCs #1 and #2, and a DL CC#2 correspond to UL CCs #2 and #4. Meanwhile, from a viewpoint of UE,there are one transport block and one hybrid automatic repeat request(HARQ) entity in each scheduled CC. Each transport block is mapped toone CC only. UE may be mapped to a plurality of CCs at the same time.

In an LTE-A system, there may be a backward-compatible carrier and anon-backward-compatible carrier. The backward-compatible carrier is acarrier capable of accessing the UEs of all LTE releases including LTErel-8 and LTE-A. The backward-compatible carrier may be operated as asingle carrier or may be operated as a CC in a carrier aggregationsystem. The backward-compatible carrier may be always formed of a pairof uplink and downlink in an FDD system. In contrast, thenon-backward-compatible carrier cannot access the UE of a previous LTErelease, but can access only the UEs of an LTE release that defines thenon-backward-compatible carrier. Furthermore, thenon-backward-compatible carrier may be operated as a single carrier ormay be operated as a CC in a carrier aggregation system. Meanwhile, acarrier that cannot be operated as a single carrier, but that isincluded in a carrier aggregation including at least one carrier capableof being operated as a single carrier may be called an extensioncarrier.

Furthermore, in a carrier aggregation system, a type in which one ormore carriers are used may include two types: a cell-specific carrieraggregation system operated by a specific cell or BS and a UE-specificcarrier aggregation system operated by UE. If a cell means onebackward-compatible carrier or one non-backward-compatible carrier, theterm ‘cell-specific’ may be used for one or more carriers which includeone carrier represented by a cell. Furthermore, in the type of a carrieraggregation system in an FDD system, the linkage of uplink and downlinkmay be determined depending on default transmission-reception (Tx-Rx)separation defined in LTE rel-8 or LTE-A.

For example, in LTE rel-8, default Tx-Rx separation is as follows. Inuplink and downlink, a carrier frequency may be allocated within a rangeof 0˜65535 according to an E-UTRA absolute radio frequency channelnumber (EARFCN). In downlink, a relationship between the EARFCN and acarrier frequency of a MHz unit may be represented by F_(DL)=F_(DL) _(_)_(low)+0.1(N_(DL)−N_(Offs-DL)). In uplink, a relationship between theEARFCN and a carrier frequency of a MHz unit may be represented byF_(UL)=F_(UL) _(_) _(low)+0.1(N_(UL)−N_(Offs-UL)). N_(DL) is a downlinkEARFCN, and N_(UL) is an uplink EARFCN. F_(DL-low), N_(Offs-DL),F_(UL-low), and N_(Offs-UL) may be determined by Table 1.

TABLE 1 E-UTRA Downlink Uplink Operating F_(DL) _(—) _(low) Range F_(UL)_(—) _(low) Range Band (MHz) N_(Offs-DL) of N_(DL) (MHz) N_(Offs-UL) ofN_(UL) 1 2110 0  0-599 1920 18000 18000-18599 2 1930 600  600-1199 185018600 18600-19199 3 1805 1200 1200-1949 1710 19200 19200-19949 4 21101950 1950-2399 1710 19950 19950-20399 5 869 2400 2400-2649 824 2040020400-20649 6 875 2650 2650-2749 830 20650 20650-20749 7 2620 27502750-3449 2500 20750 20750-21449 8 925 3450 3450-3799 880 2145021450-21799 9 1844.9 3800 3800-4149 1749.9 21800 21800-22149 10 21104150 4150-4749 1710 22150 22150-22749 11 1475.9 4750 4750-4999 1427.922750 22750-22999 12 728 5000 5000-5179 698 23000 23000-23179 13 7465180 5180-5279 777 23180 23180-23279 14 758 5280 5280-5379 788 2328023280-23379 . . . 17 734 5730 5730-5849 704 23730 23730-23849 . . . 331900 26000 36000-36199 1900 36000 36000-36199 34 2010 26200 36200-363492010 36200 36200-36349 35 1850 26350 36350-36949 1850 36350 36350-3694936 1930 26950 36950-37549 1930 36950 36950-37549 37 1910 2755037550-37749 1910 37550 37550-37749 38 2570 27750 37750-38249 2570 3775037750-38249 39 1880 28250 38250-38649 1880 38250 38250-38649 40 230028650 38650-39649 2300 38650 38650-39649

The basic separation of an E-TURA Tx channel and Rx channel may bedetermined by Table 2.

TABLE 2 Frequency Band TX-RX carrier centre frequency separation 1 190MHz  2 80 MHz 3 95 MHz 4 400 MHz  5 45 MHz 6 45 MHz 7 120 MHz  8 45 MHz9 95 MHz 10 400 MHz  11 48 MHz 12 30 MHz 13 −31 MHz  14 −30 MHz  17 30MHz

Hereinafter, an uplink reference signal (RS) will be described.

In general, an RS is transmitted as a sequence. Any sequence can be usedas a sequence used for an RS sequence without particular restrictions.The RS sequence may be a phase shift keying (PSK)-based computergenerated sequence. Examples of the PSK include binary phase shiftkeying (BPSK), quadrature phase shift keying (QPSK), etc. Alternatively,the RS sequence may be a constant amplitude zero auto-correlation(CAZAC) sequence. Examples of the CAZAC sequence include a Zadoff-Chu(ZC)-based sequence, a ZC sequence with cyclic extension, a ZC sequencewith truncation, etc. Alternatively, the RS sequence may be apseudo-random (PN) sequence. Example of the PN sequence include anm-sequence, a computer generated sequence, a Gold sequence, a Kasamisequence, etc. In addition, the RS sequence may be a cyclically shiftedsequence.

The uplink RS can be classified into a demodulation reference signal(DMRS) and a sounding reference signal (SRS). The DMRS is an RS used forchannel estimation to demodulate a received signal. The DMRS can becombined with PUSCH or PUCCH transmission. The SRS is an RS transmittedfor uplink scheduling by a UE to a BS. The BS estimates an uplinkchannel by using the received SRS, and the estimated uplink channel isused in uplink scheduling. The SRS is not combined with PUSCH or PUCCHtransmission. The same type of base sequences can be used for the DMRSand the SRS. Meanwhile, precoding applied to the DMRS in uplinkmulti-antenna transmission may be the same as precoding applied to thePUSCH. Cyclic shift separation is a primary scheme for multiplexing theDMRS. In an LTE-A system, the SRS may not be precoded, and may be anantenna-specific RS.

The SRS is an RS transmitted by a relay station to the BS and is an RSwhich is not related to uplink data or control signal transmission. Ingeneral, the SRS may be used for channel quality estimation forfrequency selective scheduling in uplink or may be used for otherusages. For example, the SRS may be used in power control, initial MCSselection, initial power control for data transmission, etc. In general,the SRS is transmitted in a last SC-FDMA symbol of one subframe.

An operation in UE for the transmission of an SRS is as follows.C_(SRS), that is, a cell-specific SRS transmission bandwidth may begiven by a higher layer, and a cell-specific SRS transmission subframemay be given by a higher layer. If UE can select a transmit antenna, theindex a(n_(SRS)) of a UE antenna that transmits an SRS at a time n_(SRS)is given a(n_(SRS))=n_(SRS) mod 2 for the full sounding bandwidth or thepartial sounding bandwidth when frequency hopping is not available andmay be given by Equation 2 when frequency hopping is available.

$\begin{matrix}{{a\left( n_{S\; R\; S} \right)} = \left\{ \begin{matrix}{\left( {n_{S\; R\; S} + \left\lfloor {n_{S\; R\; S}/2} \right\rfloor + {\beta \cdot \left\lfloor {n_{S\; R\; S}/K} \right\rfloor}} \right){mod}\; 2} & {{when}\mspace{14mu} K\mspace{14mu} {is}\mspace{14mu} {even}} \\{n_{S\; R\; S}\; {mod}\; 2} & {{when}\mspace{14mu} K\mspace{14mu} {is}\mspace{14mu} {odd}}\end{matrix} \right.} & {\langle{{Equation}\mspace{14mu} 2}\rangle}\end{matrix}$

In Equation 2, B_(SRS) indicates an SRS bandwidth, and b_(hop) indicatesa frequency hopping bandwidth. N_(b) may be determined by apredetermined table according to C_(SRS) and B_(SRS).

$K = {\prod\limits_{b^{\prime} = b_{hop}}^{B_{S\; R\; S}}\; {N_{b^{\prime}}.}}$

In Equation 2, β may be determined by Equation 3.

$\begin{matrix}{\beta = \left\{ \begin{matrix}1 & {{{where}\mspace{14mu} K\mspace{14mu} {mod}\; 4} = 0} \\0 & {otherwise}\end{matrix} \right.} & {\langle{{Equation}\mspace{14mu} 3}\rangle}\end{matrix}$

If one SC-FDMA symbol exists within an uplink pilot time slot (UpPTS) ina TDD system, the one SC-FDMA symbol may be used for SRS transmission.If two SC-FDMA symbols exist within an UpPTS, both the two SC-FDMAsymbols may be used for SRS transmission and may be allocated to one UEat the same time.

UE does not always transmit an SRS whenever the transmission of an SRSand the transmission of PUCCH format 2/2a/2b occur within the samesubframe at the same time.

If an ackNackSRS-SimultaneousTransmission parameter is false, UE doesnot always transmit an SRS whenever the transmission of an SRS and thetransmission of a PUCCH that carries ACK/NACK and/or a positive SR areperformed in the same subframe. Furthermore, if anackNackSRS-SimultaneousTransmission parameter is true, UE uses ashortened PUCCH format and transmits a PUCCH that carries ACK/NACKand/or a positive SR and an SRS at the same time when the transmissionof the SRS and the transmission of the PUCCH that carries ACK/NACKand/or a positive SR are configured in the same subframe. That is, if aPUCCH that carries ACK/NACK and/or a positive SR and an SRS isconfigured within an SRS subframe configured in a cell specific manner.UE uses a shortened PUCCH format and transmits the PUCCH that carriesACK/NACK and/or a positive SR and the SRS at the same time. If SRStransmission overlaps with a physical random access channel (PRACH)region for the preamble format 4 or exceeds the range of an uplinksystem bandwidth configured in a cell, UE does not transmit an SRS.

ackNackSRS-SimultaneousTransmission, that is, a parameter given by ahigher layer, determines whether UE supports the simultaneoustransmission of a PUCCH that carries ACK/NACK and an SRS within onesubframe. If UE is configured to transmit a PUCCH that carries ACK/NACKand an SRS within one subframe at the same time, the UE may transmitsthe ACK/NACK and the SRS in a cell-specific SRS subframe. Here, ashortened PUCCH format may be used, and the transmission of ACK/NACK oran SR corresponding to a position where the SRS is transmitted ispunctured. The shortened PUCCH format is used in the cell-specific SRSsubframe even when the UE does not transmit the SRS in the relevantsubframe. If UE is configured not to transmit a PUCCH that carriesACK/NACK and an SRS within one subframe at the same time, the UE may usecommon PUCCH formats 1/1a/1b in order to transmit the ACK/NACK and theSR.

Tables 3 and 4 are examples of a UE-specific SRS configuration thatindicates T_(SRS), that is, an SRS transmission periodicity, andT_(offset), that is, an SRS subframe offset. The SRS transmissionperiodicity T_(SRS) may be determined as one of {2, 5, 10, 20, 40, 80,160, 320} ms.

Table 3 is an example of an SRS configuration in an FDD system.

TABLE 3 SRS Periodicity SRS Subframe Offset SRS Configuration IndexI_(SRS) T_(SRS) (ms) T_(offset) 0-1 2 I_(SRS) 2-6 5 I_(SRS)-2  7-16 10I_(SRS)-7 17-36 20 I_(SRS)-17 37-76 40 I_(SRS)-37  77-156 80 I_(SRS)-77157-316 160 I_(SRS)-157 317-636 320 I_(SRS)-317  637-1023 reservedreserved

Table 4 is an example of an SRS configuration in a TDD system.

TABLE 4 Configuration SRS Periodicity SRS Subframe Index I_(SRS) T_(SRS)(ms) Offset T_(offset) 0 2 0, 1 1 2 0, 2 2 2 1, 2 3 2 0, 3 4 2 1, 3 5 20, 4 6 2 1, 4 7 2 2, 3 8 2 2, 4 9 2 3, 4 10-14 5 I_(SRS)-10 15-24 10I_(SRS)-15 25-44 20 I_(SRS)-25 45-84 40 I_(SRS)-45  85-164 80 I_(SRS)-85165-324 160 I_(SRS)-165 325-644 320 I_(SRS)-325  645-1023 reservedreserved

In the case of T_(SRS)>2 in a TDD system, an SRS subframe in an FDDsystem satisfy (10*n_(f)+k_(SRS)−T_(offset)) mod T_(SRS)=0. n_(f)indicates a frame index, and k_(SRS) is a subframe index within a framein an FDD system. In the case of T_(SRS)=2 in a TDD system, 2 SRSresources may be configured within a half frame including at least oneuplink subframe, and an SRS subframe satisfies(k_(SRS)−T_(offset))mod5=0.

In a TDD system, k_(SRS) may be determined by Table 5.

TABLE 5 Subframe index n 1 6 1^(st) symbol of 2^(nd) symbol of 1^(st)symbol 2^(nd) symbol 0 UpPTS UpPTS 2 3 4 5 of UpPTS of UpPTS 7 8 9k_(SRS) in case UpPTS 0 1 2 3 4 5 6 7 8 9 length of 2 symbols k_(SRS) incase UpPTS 1 2 3 4 6 7 8 9 length of 1 symbol

Meanwhile, UE does not always transmit an SRS if the transmission of theSRS and the transmission of a PUSCH, corresponding to the retransmissionof the same transport block as part of a random access response grant ora contention-based random access procedure, are performed within thesame subframe.

Channel coding for PUSCH transmission is described below.

FIG. 10 is an example of a process of processing an uplink sharedchannel (UL-SCH) transport channel. A coding unit is reached in the formof one maximum transport block at each transmit time interval (TTI).

Referring to FIG. 10, at step S100, a cyclic redundancy check (CRC) isattached to a transport block. When the CRC is attached, error detectionfor an UL-SCH transport block can be supported. All transport blocks maybe used to calculate a CRC parity bit. Bits within a transport blocktransferred in a layer 1 are a₀, . . . , a_(A-1), and parity bits may berepresented by p₀, . . . , p_(L-1). The size of the transport block isA, and the size of the parity bit is L. a0, that is, the information bitof the smallest order, may be mapped to the most significant bit (MSB)of the transport block.

At step S110, the transport block to which the CRC is attached issegmented into a plurality of code blocks, and a CRC is attached to eachof the code blocks. Bits before they are segmented into the code blocksmay be represented by b₀, . . . , b_(B-1), and B is the number of bitswithin the transport block including the CRC. Bits after they aresegmented into the code blocks may be represented by c_(r0), . . . ,c_(r(Kr-1)), r is a code block number, and Kr is the number of bits ofthe code block number r.

At step S120, channel coding is performed on each of the code blocks.The total number of code blocks is C, and the channel coding may beperformed on each code block according to a turbo coding scheme. Thebits on which the channel coding has been performed may be representedby d_(r0) ^((i)), . . . , d_(r(Dr-1)) ^((i)), and D_(r) is the number ofbits of an i^(th) coded stream of the code block number r. D_(r)=Kr+4,and i is a coded stream index and may be 0, 1 or 2.

At step S130, rate matching is performed on each code block on which thechannel coding has been performed. The rate matching may be performedfor code block individually. Bits after the rate matching is performedmay be represented by e_(r0), . . . , e_(r(Er-1)), r is a code blocknumber, and E_(r) is the number of rate matched bits of the code blocknumber r.

At step S140, the code blocks on which the rate matching has beenperformed are concatenated. Bits after the code blocks are concatenatedmay be represented by f₀, . . . , f_(G-1), and G is the total number ofcoded transmission bits other than bits that are used to transmitcontrol information. Here, the control information may be multiplexedwith UL-SCH transmission.

At steps S141 to S143, channel coding is performed on the controlinformation. The control information may include channel qualityinformation (CQI) and/or CQI including a precoding matrix indicator(PMI), hybrid automatic repeat request (HARQ)-acknowledgement (ACK), anda rank indicator (RI). Or, it is hereinafter assumed that the CQIincludes a PMI. A different coding rate is applied to each piece ofcontrol information depending on the number of different coding symbols.When the control information is transmitted in a PUSCH, channel codingon CQI, an RI, and HARQ-ACK is independently performed. In the presentembodiment, it is assumed that the channel coding is performed on CQI atstep S141, the channel coding is performed on an RI at step S142, andthe channel coding is performed on HARQ-ACK at step S143, but notlimited thereto.

In a TDD system, two types of HARQ-ACK feedback modes of HARQ-ACKbundling and HARQ-ACK multiplexing may be supported by a higher layer.In the TDD HARQ-ACK bundling mode, HARQ-ACK includes one or twoinformation bits. In the TDD HARQ-ACK multiplexing mode, HARQ-ACKincludes one to four information bits.

If UE transmits HARQ-ACK bits or RI bits, the number of coded symbols Q′may be determined by Equation 4.

$\begin{matrix}{Q^{\prime} = {\min {\quad\left( {\left\lceil \frac{O \cdot M_{sc}^{{PUSCH} - {initial}} \cdot N_{symb}^{{PUSCH} - {initial}} \cdot \beta_{offset}^{PUSCH}}{\sum\limits_{r = 0}^{C - 1}\; K_{r}} \right\rceil, {4 \cdot M_{sc}^{PUSCH}}} \right)}}} & {\langle{{Equation}\mspace{14mu} 4}\rangle}\end{matrix}$

In Equation 4, O is the number of HARQ-ACK bits or RI bits, and M_(sc)^(PUSCH) is a bandwidth scheduled for PUSCH transmission in the currentsubframe of a transport block which is represented by the number ofsubcarriers. N_(symb) ^(PUSCH-initial) is the number of SC-FDMA symbolsin each subframe for initial PUSCH transmission in the same transportblock and may be determined as N_(symb) ^(PUSCH-initial)=(2*(N_(symb)^(UL)−1)−N_(SRS)). If UE is configured to transmit a PUSCH and an SRS inthe same subframe for initial transmission or the allocation of PUSCHresources for initial transmission partially overlaps with a bandwidthallocated for the transmission of a cell-specific SRS subframe and SRS,N_(SRS)=1. In the remaining cases, N_(SRS)=0. M_(sc) ^(PUSCH-initial),C, and Kr may be obtained from an initial PDCCH for the same transportblock. If there is no DCI format 0 within the initial PDCCH for the sametransport block, M_(sc) ^(PUSCH-initial), C, and Kr may be obtained froma PDCCH that has been semi-persistently allocated most recently when theinitial PUSCH for the same transport block has been semi-persistentlyscheduled and may be obtained from a random access response grant forthe same transport block when a PUSCH has been initiated from a randomaccess response grant.

In HARQ-ACK transmission, Q_(ACK)=Q_(m)*Q′, β_(offset)^(PUSCH)=β_(offset) ^(HARQ-ACK). Furthermore, in RI transmission,Q_(RI)=Q_(m)*Q′, β_(offset) ^(PUSCH)=β_(offset) ^(RI).

In HARQ-ACK transmission, ACK may be encoded into ‘1’ from a binarynumber, and NACK may be encoded into ‘0’ from a binary number. IfHARQ-ACK is [o₀ ^(ACK)] including 1-bit information, the HARQ-ACK may beencoded according to Table 6.

TABLE 6 Q_(m) Encoded HARQ-ACK 2 [O₀ ^(ACK) y] 4 [O₀ ^(ACK) y x x] 6 [O₀^(ACK) y x x x x

If HARQ-ACK is [o₀ ^(ACK) o₁ ^(ACK)] including 2-bit information, theHARQ-ACK may be encoded according to Table 7. In Table 7, o₂ ^(ACK)=(o₀^(ACK)+o₁ ^(ACK))mod2.

TABLE 7 Q_(m) Encoded HARQ-ACK 2 [O₀ ^(ACK) O₁ ^(ACK) O₂ ^(ACK) O₀^(ACK) O₁ ^(ACK) O₂ ^(ACK)] 4 [O₀ ^(ACK) O₁ ^(ACK) x x O₂ ^(ACK) O₀^(ACK) x x O₁ ^(ACK) O₂ ^(ACK) x x] 6 [O₀ ^(ACK) O₁ ^(ACK) x x x x O₂^(ACK) O₀ ^(ACK) x x x x O₁ ^(ACK) O₂ ^(ACK) x x x x]

In Tables 6 and 7, x and y indicate placeholders for scrambling HARQ-ACKbits for a method of maximizing the Euclidean distance of a modulationsymbol for carrying HARQ-ACK information.

When HARQ-ACK includes one or two information bits, in the case of theFDD or TDD HARQ-ACK multiplexing mode, a bit sequence q₀ ^(ACK), . . . ,q_(QACK-1) ^(ACK) may be obtained by concatenating a plurality ofencoded HARQ-ACK block. Here, Q_(ACK) is the total number of encodedbits within all the encoded HARQ-ACK blocks. The concatenation of thelast HARQ-ACK block may be partially performed in order to match thetotal length of the bit sequence with Q_(ACK).

In the case of the TDD HARQ-ACK bundling mode, a bit sequence {tildeover (q)}₀ ^(ACK), . . . , {tilde over (q)}_(Q) _(ACK) ₋₁ ^(ACK) may beobtained by concatenating a plurality of encoded HARQ-ACK blocks. Here,Q_(ACK) is the total number of encoded bits within all the encodedHARQ-ACK blocks. The concatenation of the last HARQ-ACK block may bepartially performed in order to match the total length of the bitsequence with Q_(ACK). A scrambling sequence [w₀ ^(ACK) w₁ ^(ACK) w₂^(ACK) w₃ ^(ACK)] may be determined by Table 8.

TABLE 8 i [w₀ ^(ACK) w₁ ^(ACK) w₂ ^(ACK) w₃ ^(ACK)] 0 [1 1 1 1] 1 [1 0 10] 2 [1 1 0 0] 3 [1 0 0 1]

If HARQ-ACK is [o₀ ^(ACK) o_(OACK-1) ^(ACK)] including two or higherinformation bits (O^(ACK)>2), a bit sequence q₀ ^(ACK), . . . q_(QACK-1)^(ACK) may be obtained by Equation 5.

$\begin{matrix}{q_{i}^{ACK} = {\sum\limits_{n = 0}^{O^{ACK} - 1}\; {\left( {o_{n}^{ACK} \cdot M_{{({i\; {mod}\; 32})},n}} \right){mod}\; 2}}} & {\langle{{Equation}\mspace{14mu} 5}\rangle}\end{matrix}$

In Equation 5, i=0, . . . , Q_(ACK)−1.

In RI transmission, the size of a bit of RI feedback corresponding toPDSCH transmission may be determined by assuming a maximum number oflayers according to the antenna configuration of a BS and UE. If an RIis [o₀ ^(RI)] including 1-bit information, the RI may be encodedaccording to Table 9.

TABLE 9 Q_(m) Encoded RI 2 [o0RI y] 4 [o0RI y x x] 6 [o0RI y x x x x

In Table 9, the mapping of [o₀ ^(RI)] and an RI may be given by Table10.

TABLE 10 o0RI RI 0 1 1 2

If an RI is [o₀ ^(RI) o₁ ^(RI)] including 2-bit information, o₀ ^(RI)corresponds to an MSB from the 2-bit information, and o₁ ^(RI)corresponds to the least significant bit (LSB) of 2 bits, the RI may beencoded according to Table 11. In Table 11, o₂ ^(RI)=(o₀ ^(RI)+o₁^(RI))mod2.

TABLE 11 Q_(m) Encoded RI 2 [O₀ ^(RI) O₁ ^(RI) O₂ ^(RI) O₀ ^(RI) O₁^(RI) O₂ ^(RI)] 4 [O₀ ^(RI) O₁ ^(RI) x x O₂ ^(RI) O₀ ^(RI) x x O₁ ^(RI)O₂ ^(RI) x x] 6 [O₀ ^(RI) O₁ ^(RI) x x x x O₂ ^(RI) O₀ ^(RI) x x x x O₁^(RI) O₂ ^(RI) x x x x]

In Table 11, the mapping of [o₀ ^(RI) o₁ ^(RI)] and an RI may be givenby Table 12.

TABLE 12 O₀ ^(RI) · O₁ ^(RI) RI 0, 0 1 0, 1 2 1, 0 3 1, 1 4

In Tables 6 and 7, x and y indicate placeholders for scrambling HARQ-ACKbits for a method of maximizing the Euclidean distance of a modulationsymbol for carrying HARQ-ACK information.

A bit sequence q₀ ^(RI), . . . , q_(QRI-1) ^(RI) may be obtained byconcatenating a plurality of encoded RI blocks. Here, Q_(RI) is thetotal number of encoded bits within all the encoded RI blocks. Theconcatenation of the last RI block may be partially performed in orderto match the total length of the bit sequence with Q_(RI).

If UE transmits CQI bits, the number of coded symbols Q′ may bedetermined by Equation 6.

$\begin{matrix}{Q^{\prime} = {\min {\quad\left( {\left\lceil \frac{\begin{matrix}{\left( {O + L} \right) \cdot M_{sc}^{{PUSCH} - {initial}} \cdot} \\{N_{symb}^{{PUSCH} - {initial}} \cdot \beta_{offset}^{PUSCH}}\end{matrix}}{\sum\limits_{r = 0}^{C - 1}\; K_{r}} \right\rceil, {{M_{sc}^{PUSCH} \cdot N_{symb}^{PUSCH}} - \frac{Q_{RI}}{Q_{m}}}} \right)}}} & {\langle{{Equation}\mspace{14mu} 6}\rangle}\end{matrix}$

In Equation 6, O is the number of CQI bits, and L is the number of CRCbits which is given 0 when O≦11 and given 8 in other cases. Furthermore,Q_(CQI)=Q_(m)*Q′, and β_(offset) ^(PUSCH)=β_(offset) ^(CQI). If an RI isnot sent, Q_(RI)=0. M_(sc) ^(PUSCH-initial), C and K_(r) may be obtainedfrom an initial PDCCH for the same transport block. If the DCI format 0does not exist within the initial PDCCH for the same transport block,M_(sc) ^(PUSCH-initial), C, and K_(r) may be obtained from a PDCCH thathas been semi-persistently allocated most recently when the initialPUSCH for the same transport block has been semi-persistently scheduledand may be obtained from a random access response grant for the sametransport block when a PUSCH has been initiated from a random accessresponse grant. N_(symb) ^(PUSCH-initial) is the number of SC-FDMAsymbols in each subframe for the transmission of the initial PUSCH inthe same transport block. Regarding UL-SCH data information, G=N_(symb)^(PUSCH)*M_(sc) ^(PUSCH)*Q_(m)-Q_(CQI)-Q_(R). Here, M_(sc) ^(PUSCH) is abandwidth scheduled for PUSCH transmission in the current subframe of atransport block which is represented by the number of subcarriers.N_(symb) ^(PUSCH)=(2*(N_(symb) ^(UL)−1)-N_(SRS)). If UE is configured totransmit a PUSCH and an SRS in the same subframe for initialtransmission or the allocation of PUSCH resources for the initialtransmission partially overlaps with a bandwidth allocated to thetransmission of a cell-specific SRS subframe and SRS, N_(SRS)=1. Inother cases, N_(SRS)=0.

In CQI transmission, when the size of a payload is smaller than 11 bits,the channel coding of CQI information is performed based on an inputsequence o₀, . . . , o_(O-1). When the size of a payload is greater than11 bits, CRC addition, channel coding, and rate matching are performedon the CQI information. The input sequence of the CRC attachment processis o₀, . . . , o_(O-1). An output sequence to which the CRC has beenattached becomes the input sequence of the channel coding process, andthe output sequence of the channel coding process becomes the inputsequence of the rate matching process. The output sequence of the finalchannel coding on the CQI information may be represented by q₀, . . . ,q_(QCQI-1).

At step S150, multiplexing is performed on the data and the controlinformation. Here, the HARQ-ACK information exists both in the two slotsof a subframe, and it may be mapped to resources adjacent to a DMRS.When the data and the control information are multiplexed, they may bemapped to different modulation symbols. Meanwhile, if one or more UL-SCHtransport blocks are transmitted in the subframe of an uplink cell, CQIinformation may be multiplexed with data on an UL-SCH transport blockhaving the highest modulation and coding scheme (MCS).

At step S160, channel interleaving is performed. The channelinterleaving may be performed in connection with PUSCH resource mapping.Modulation symbols may be mapped to a transmit waveform in a time-firstmapping manner through the channel interleaving. The HARQ-ACKinformation may be mapped to resources adjacent to an uplink DMRS, andthe RI information may be mapped to the periphery of resources used bythe HARQ-ACK information.

A proposed SRS transmission method is described below in connection withembodiments.

The SRS transmission method may be divided into two types: a periodicSRS transmission method of transmitting an SRS periodically according toan SRS parameter received by radio resource control (RRC) signaling,which is a method defined in LTE rel-8, and an aperiodic SRStransmission method of transmitting an SRS whenever the SRS is necessarybased on a message dynamically triggered by a BS. In LTE-A, theaperiodic SRS transmission method may be introduced.

In the periodic SRS transmission method and the aperiodic SRStransmission method, an SRS may be transmitted in a UE-specific SRSsubframe determined in a UE-specific manner. In the periodic SRStransmission method defined in LTE rel-8, a cell-specific SRS subframeis periodically configured by a cell-specific SRS parameter, and aperiodic SRS is transmitted in a periodic UE-specific SRS subframe thatis configured by a UE-specific SRS parameter from the cell-specific SRSsubframe. Here, the periodic UE-specific SRS subframe may be a subset ofthe cell-specific SRS subframe. The cell-specific SRS parameter may begiven by a higher layer. In the aperiodic SRS transmission method, anaperiodic SRS may be transmitted in an aperiodic UE-specific SRSsubframe determined by a UE-specific aperiodic SRS parameter. TheUE-specific SRS subframe of the aperiodic SRS transmission method may bea subset of the cell-specific SRS subframe as defined in LTE rel-8. Or,the aperiodic UE-specific SRS subframe may be identical with thecell-specific SRS subframe. Like the cell-specific SRS parameter, theUE-specific aperiodic SRS parameter may be given by a higher layer. TheUE-specific aperiodic SRS subframe may be determined by the periodicityof the subframe and the offset of the subframe in Table 3 or Table 4described above.

In an SRS subframe determined in a UE-specific manner or determined in acell specific manner, the operation of UE when a PUSCH and an aperiodicSRS are configured so that they are transmitted at the same time has notyet been defined. Accordingly, there is a need for a data transmissionmethod as a new operation of UE when a PUSCH and an aperiodic SRS areconfigured so that they are transmitted at the same time.

FIG. 11 is an example of a configuration regarding the proposed methodof transmitting data in an SRS subframe.

In FIG. 11, an SRS subframe is any one of aperiodic UE-specific SRSsubframes determined in a UE-specific manner. Or, if the aperiodicUE-specific SRS subframe is identical with an SRS subframe determined ina cell specific manner, the SRS subframe of FIG. 11 is any one of SRSsubframes determined in a cell specific manner. The last SC-FDMA symbolof the SRS subframe is allocated for SRS transmission, and a PUSCH maybe allocated to the remaining SC-FDMA symbols and data may betransmitted. In the last SC-FDMA symbol of the SRS subframe, a bandwidthoccupied by the SRS may be the entire system bandwidth and may be anarrow band or partial bandwidth. Furthermore, the bandwidth occupied bythe SRS may be a UE-specific SRS bandwidth defined in LTE rel-8/9 andmay be an SRS bandwidth newly configured in LTE-A. In the remainingSC-FDMA symbols, a bandwidth occupied by a PUSCH is also not limited.

The SRS and uplink data through a PUSCH are transmitted in the SRSsubframe at the same time. Here, the PUSCH may be subject to ratematching except the last SC-FDMA symbol allocated to the SRS. Thetransmission of a PUSCH in a relevant SRS subframe may be subject torate matching so that the PUSCH is transmitted in the remaining SC-FDMAsymbols in which the SRS is not transmitted without a limitation to arelationship between the transmission bandwidth of the SRS and abandwidth occupied by the PUSCH. As the PUSCH is subject to the ratematching, the data rate corresponding to one SC-FDMA symbol when data istransmitted through the PUSCH is reduced, and reliability and coverageof SRS transmission can be improved.

Or, a PUSCH allocated to the last SC-FDMA symbol may be puncturedwithout performing rate matching on the PUSCH. Furthermore, in FIG. 11,the case where the SRS is transmitted in the last SC-FDMA symbolallocated to the SRS has been assumed, but the present invention mayalso be applied to the case where the SRS subframe is allocated by aUE-specific SRS parameter and the SRS is not actually transmitted. Thatis, in an aperiodic UE-specific SRS subframe or cell-specific SRSsubframe, a PUSCH may be subject to rate matching except the lastSC-FDMA symbol allocated to an SRS irrespective of whether an SRS hasbeen transmitted or not.

FIG. 12 is an embodiment of the proposed data transmission method. Atstep S100, UE transmits uplink data in an SRS subframe on an SRS and aPUSCH. Here, an SC-FDMA symbol allocated to the SRS and an SC-FDMAsymbol allocated to the PUSCH do not overlap with each other within theSRS subframe, and rate matching is performed on the PUSCH.

FIG. 13 is an embodiment of the proposed resource mapping method. Atstep S100, UE allocates PUSCH resources except reserved SC-FDMA symbolsin order to transmit an aperiodic SRS. Physical resource blocksallocated to transmit a PUSCH are mapped to relevant resource elements(REs) within the subframe. The subframe may be any one of aperiodicUE-specific SRS subframes determined in a UE-specific manner or may beany one of SRS subframes determined in a cell specific manner.

The proposed resource mapping method may be applied to channel coding onthe PUSCH transmission of FIG. 10. More particularly, in Equation 4 thatdetermines the number of symbols coded when HARQ-ACK and/or an RI aretransmitted, N_(symb) ^(PUSCH-initial) may be changed. That is, N_(symb)^(PUSCH-initial) is the number of SC-FDMA symbols in each subframe forinitial PUSCH transmission in the same transport block and may bedetermined as N_(symb) ^(PUSCH-initial)=(2*(N_(symb) ^(UL)−1)-N_(SRS)).Here, if UE is configured to transmit a PUSCH and an SRS in the samesubframe for initial transmission, the allocation of PUSCH resources forthe initial transmission partially overlaps with a bandwidth allocatedfor the transmission of a UE-specific SRS subframe and an SRS, or UEtransmits a PUSCH in a cell-specific SRS subframe when aperiodic SRStransmission is configured, N_(SRS)=1. In the remaining cases,N_(SRS)=0. Or, in Equation 6 that determines the number of symbols codedwhen CQI is transmitted, N_(symb) ^(PUSCH) may be changed. That is,N_(symb) ^(PUSCH) may be determined as N_(symb) ^(PUSCH)=(2*(N_(symb)^(UL)−1)-N_(SRS)). Here, if UE is configured to transmit a PUSCH and anSRS in the same subframe for initial transmission, the allocation ofPUSCH resources for the initial transmission partially overlaps with abandwidth allocated for the transmission of a UE-specific SRS subframeand an SRS, or UE transmits a PUSCH in a cell-specific SRS subframe whenaperiodic SRS transmission is configured, N_(SRS)=1. In the remainingcases, N_(SRS)=0.

FIG. 14 is another example of a configuration regarding the proposedmethod of transmitting data in an SRS subframe. Referring to FIG. 14,uplink data is transmitted through a PUSCH over the entire SRS subframe,and the transmission of an SRS is dropped. Accordingly, the data rate ofPUSCH transmission and quality of service (QoS) of data transmittedthrough a PUSCH can be guaranteed.

Or, the rate matching of a PUSCH in FIG. 11 and the dropping of an SRSin FIG. 14 may be determined through an RRC message. Here, either thePUSCH rate matching method or the SRS dropping method may be selected inresponse to the RRC message that indicates the simultaneous transmissionof a PUSCH and a PUCCH. Or, either the PUSCH rate matching method or theSRS dropping method may be selected in response to a newly defined RRCmessage.

FIG. 15 is a block diagram of a BS and UE in which the embodiments ofthe present invention are embodied.

The BS 800 includes a processor 810, memory 820, and a radio frequency(RF) unit 830. The processor 810 implements the proposed functions,processes and/or methods. The layers of a radio interface protocol maybe implemented by the processor 810. The memory 820 is connected to theprocessor 810, and it stores various pieces of information for drivingthe processor 810. The RF unit 830 is connected to the processor 810,and it transmits and/or receives radio signals.

The UE 900 includes a processor 910, memory 920, and an RF unit 930. TheRF unit 930 is connected to the processor 910, and it transmits uplinkdata on an SRS and a PUSCH in an SRS subframe. The processor 910implements the proposed functions, processes and/or methods. The layersof a radio interface protocol may be implemented by the processor 910.The memory 920 is connected to the processor 910, and its stores variouspieces of information for driving the processor 910.

The processor 910 may include an application-specific integrated circuit(ASIC), another chip set, a logical circuit, and/or a data processingunit. The RF unit 920 may include a baseband circuit for processingradio signals. In software implemented, the aforementioned methods canbe implemented with a module (i.e., process, function, etc.) forperforming the aforementioned functions. The module may be performed bythe processor 910. In view of the exemplary systems described herein,methodologies that may be implemented in accordance with the disclosedsubject matter have been described with reference to several flowdiagrams. While for purposed of simplicity, the methodologies are shownand described as a series of steps or blocks, it is to be understood andappreciated that the claimed subject matter is not limited by the orderof the steps or blocks, as some steps may occur in different orders orconcurrently with other steps from what is depicted and describedherein. Moreover, one skilled in the art would understand that the stepsillustrated in the flow diagram are not exclusive and other steps may beincluded or one or more of the steps in the example flow diagram may bedeleted without affecting the scope and spirit of the presentdisclosure.

What has been described above includes examples of the various aspects.It is, of course, not possible to describe every conceivable combinationof components or methodologies for purposes of describing the variousaspects, but one of ordinary skill in the art may recognize that manyfurther combinations and permutations are possible. Accordingly, thesubject specification is intended to embrace all such alternations,modifications and variations that fall within the spirit and scope ofthe appended claims.

What is claimed is:
 1. A method for transmitting, by a user equipment(UE), uplink data in a wireless communication system, the methodcomprising: mapping uplink data to resource elements corresponding to aphysical uplink shared channel (PUSCH) in a UE-specific aperiodicsounding reference signal (SRS) subframe, wherein the UE-specificaperiodic SRS subframe includes a single carrier frequency divisionmultiple access (SC-FDMA) symbol reserved for an aperiodic SRS, whereinthe aperiodic SRS is transmitted in the reserved SC-FDMA symbol whentriggered by a base station, and wherein the uplink data is not mappedto the SC-FDMA symbol reserved for the aperiodic SRS regardless ofwhether the aperiodic SRS is transmitted in the reserved SC-FDMA symbolor not; and transmitting the mapped uplink data to the base station viathe UE-specific aperiodic SRS subframe.
 2. The method of claim 1,wherein the aperiodic SRS is not transmitted to the base station in theUE-specific aperiodic SRS subframe.
 3. The method of claim 1, whereinthe aperiodic SRS is transmitted to the base station in the UE-specificaperiodic SRS subframe.
 4. The method of claim 1, wherein theUE-specific aperiodic SRS subframe is one of a plurality of UE-specificsubframes configured by a UE-specific aperiodic SRS parameter.
 5. Themethod of claim 4, wherein the UE-specific aperiodic SRS parameterindicates a periodicity and an offset of the plurality of UE-specificSRS subframes.
 6. The method of claim 4, wherein the UE-specificaperiodic SRS parameter is given by a higher layer.
 7. The method ofclaim 1, wherein the SC-FDMA symbol reserved for the aperiodic SRS is alast SC-FDMA symbol of the UE-specific aperiodic SRS subframe.
 8. Themethod of claim 1, wherein the PUSCH is subject to rate matching exceptthe SC-FDMA symbol reserved for the aperiodic SRS, and wherein the ratematching is performed by determining, by the UE, a number of codedmodulation symbols.
 9. The method of claim 8, wherein the number ofcoded modulation symbols is determined based on a number of SC-FDMAsymbols per subframe for the PUSCH.
 10. The method of claim 9, whereinthe number of SC-FDMA symbols per subframe for the PUSCH is determinedbased on Equation:N _(symb) ^(PUSCH-initial)=(2·(N _(symb) ^(UL)−1)−N _(SRS)) whereN_(symb) ^(UL) denotes a number of SC-FDMA symbols in each slot in theUE-specific aperiodic SRS subframe, and N_(SRS)=1.
 11. A user equipment(UE) comprising: a memory; a radio frequency (RF) unit; and a processorcoupled to the memory and the RF unit, and configured to: map uplinkdata to resource elements corresponding to a physical uplink sharedchannel (PUSCH) in a UE-specific aperiodic sounding reference signal(SRS) subframe, wherein the UE-specific aperiodic SRS subframe includesa single carrier frequency division multiple access (SC-FDMA) symbolreserved for an aperiodic SRS, wherein the aperiodic SRS is transmittedin the reserved SC-FDMA symbol when triggered by a base station, andcontrol the RF unit to transmit the mapped uplink data to the basestation via the UE-specific aperiodic SRS subframe.
 12. The UE of claim11, wherein the aperiodic SRS is not transmitted to the base station inthe UE-specific aperiodic SRS subframe.
 13. The UE of claim 11, whereinthe aperiodic SRS is transmitted to the base station in the UE-specificaperiodic SRS subframe.
 14. The UE of claim 11, wherein the UE-specificaperiodic SRS subframe is one of a plurality of UE-specific subframesconfigured by a UE-specific aperiodic SRS parameter.
 15. The UE of claim14, wherein the UE-specific aperiodic SRS parameter indicates aperiodicity and an offset of the plurality of UE-specific SRS subframes.16. The UE of claim 14, wherein the UE-specific aperiodic SRS parameteris given by a higher layer.
 17. The UE of claim 11, wherein the SC-FDMAsymbol reserved for the aperiodic SRS is a last SC-FDMA symbol of theUE-specific aperiodic SRS subframe.
 18. The UE of claim 11, wherein thePUSCH is subject to rate matching except the SC-FDMA symbol reserved forthe aperiodic SRS, and wherein the rate matching is performed bydetermining, by the UE, a number of coded modulation symbols.
 19. The UEof claim 18, wherein the number of coded modulation symbols isdetermined based on a number of SC-FDMA symbols per subframe for thePUSCH.
 20. The UE of claim 19, wherein the number of SC-FDMA symbols persubframe for the PUSCH is determined based on Equation:N _(symb) ^(PUSCH-initial)=(2·(N _(symb) ^(UL)−1)−N _(SRS)) whereN_(symb) ^(UL) denotes a number of SC-FDMA symbols in each slot in theUE-specific aperiodic SRS subframe, and N_(SRS)=1.